In order to understand the draw of the zombie movie, you have to first get that zombie movies are pretty much never about zombies. (Like anything, there are exceptions to this rule, but not many.) They're really about our own society, and what happens to it when the basic comforts we've built collapse: What happens when the lights go out, when communication is lost, when the grocery stores become bare.

Sure, to amp up the dramatic tension, throwing undead hordes into the mix helps. But those are really just stand-ins for our own panicked selves. Because when the actual global epidemic comes, the real worry isn't going to be ambling bodies calling out for "Braaaaains," but the living calling out for "Fooooooood!"

Well, scary news folks: That day may be here sooner than we all thought.

Very basically, it simply means the amount of edible output that comes out of one space. Take grain, for example. If one seed of grain produces three grains during harvest, that has a crop yield number of 1:3. (This, theoretically, is the minimal crop yield ratio to sustain human life.) Now, something like that isn't going to go all that far, so farmers have tried a variety of ways to bump up that ratio: Crop rotation, improved waterways, and even more advanced methods like synthetic fertilizers, pesticides, and even GMOs. All of that's in an effort to change that "3" into a much higher number.

And we've done that, many times over. The problem, though, is that crop scientists have not kept pace with the world's population explosion (from 3 million in 1960 to over 7 billion today). And, bad news, some of the yields have maxed out. As in, whatever yield they currently have is what they're going to have in the future. And the population growth isn't slowing down anytime soon.

One quick effect of this plateauing is that crops are going to have to start taking over more land, namely as yet untouched wetlands, grasslands and rain forest areas (you can't expect crop yields to grow in the desert). And that kind of expansion isn't good from a lot of angles:

"These are the last bastions of carbon rich, biodiverse areas," Kenneth Cassman, an agronomist at the University of Nebraska in Lincoln and a study co-author, told NBC News. "You have a large plume of greenhouse gases emitted every time you clear those kinds of lands for agriculture."

The other option, which is already being focused on, is taking the remaining two-thirds of the planet's agricultural land not yet maxed out and continuing to prime that pump as far as possible. Much of that land resides in Africa, so researchers are focusing on ways to increase the continent's access to fertilizers and build a worthwhile infrastructure. That, as you can probably extrapolate on your own, is only a band-aid. More accurately, a withering band-aid whose sticky adhesive is already curling up in the corners.

The point is: A solution needs to come, and it needs to come quickly. Yields are maxing out, but the world's population is not slowing down. And when the food goes, so does the rest of society. Sleep tight, everyone!

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About the Author

Rick Paulas has written plenty of things, some of them serious, many of them not, scattered over the vast expanses of the Internet. He lives in Los Angeles and is a White Sox fan.
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